Editing Ultrasound (section)

== History ==
[[File:Galton whistle.jpg|thumb|Galton whistle, one of the first devices to produce ultrasound]]

[[Acoustics]], the science of [[sound]], starts as far back as [[Pythagoras]] in the 6th century BC, who wrote on the mathematical properties of [[String instrument|stringed instruments]]. [[Animal echolocation|Echolocation]] in bats was discovered by [[Lazzaro Spallanzani]] in 1794, when he demonstrated that bats hunted and navigated by inaudible sound, not vision. [[Francis Galton]] in 1893 invented the [[Dog whistle|Galton whistle]], an adjustable [[whistle]] that produced ultrasound, which he used to measure the hearing range of humans and other animals, demonstrating that many animals could hear sounds above the hearing range of humans.

The first article on the history of ultrasound was written in 1948.<ref>{{cite journal | vauthors=Klein E | title=Some background history of ultrasonics | journal=Journal of the Acoustical Society of America | year=1948 | volume=20 | issue=5 | pages=601–604 | doi=10.1121/1.1906413| bibcode=1948ASAJ...20..601K }}</ref> According to its author,
during the [[First World War]], a Russian engineer named Chilowski submitted an idea for submarine detection to the French Government. The latter invited [[Paul Langevin]], then Director of the School of Physics and Chemistry in Paris, to evaluate it. Chilowski's proposal was to excite a cylindrical, [[mica]] [[capacitor|condenser]] by a high-frequency [[Poulsen arc]] at approximately 100 kHz and thus to generate an ultrasound beam for detecting submerged objects. The idea of locating underwater obstacles had been suggested prior by L. F. Richardson, following the ''[[Titanic]]'' disaster. Richardson had proposed to position a high-frequency [[hydraulic]] [[whistle]] at the focus of a mirror and use the beam for locating submerged navigational hazards. A prototype was built by [[Sir Charles Parsons]], the inventor of the vapour [[turbine]], but the device was found not to be suitable for this purpose.
Langevin's device made use of the [[piezoelectric effect]], which he had been acquainted with whilst a student at the laboratory of [[Jacques Curie|Jacques]] and [[Pierre Curie]].<ref>{{cite book | vauthors = Pollet B | title = Power Ultrasound in Electrochemistry: From Versatile Laboratory Tool to Engineering Solution | location=Hoboken | publisher = Wiley | date = 2012 | isbn = 978-1-119-96786-6}}</ref> Langevin calculated and built an ultrasound [[transducer]] comprising a thin sheet of [[quartz]] sandwiched between two steel plates. Langevin was the first to report [[cavitation]]-related bioeffects from ultrasound.<ref>{{cite thesis | vauthors=Postema M | title=Medical Bubbles | location=Veenendaal | publisher=Universal Press | year=2004 | isbn=90-365-2037-1 | doi=10.5281/zenodo.4771630 | url=https://hal.archives-ouvertes.fr/tel-03195194/document}}</ref>